Tinker, Strength, and Possible Blindness

I spent well over an hour yesterday trying to figure out how to alter the Robo-Goblin's strength bonus, but to no avail. I'm hoping this is something so painfully obvious that I'll be called a n00b five times in the first response, but for the life of me, I can't figure it out.

So, does anyone know how to change the strength bonus that the Tinker receives when he transforms?

I don't see anything, either. I checked the forms of the units, and they both have the same initial Strength attribute, too.